A pneumatic tire is a polymeric composite and is a complex system of interacting components, each with specific properties for maximum effectiveness. One of the more important components of a tire is the tread. Since the tread of a tire comes into contact with the road, it is particularly compounded with various fillers and rubbers for traction. For example, to achieve good traction in a tire tread, the tread stock should exhibit a low rebound for increased hysteresis. Since there is a continuing effort to improve the traction of the tread of a tire, any rubber composition which exhibits improved rebound is desired.
Aside from complicated compounding of certain components of a tire, a frequent problem in making a rubber composite is maintaining good adhesion between the rubber and the reinforcement. A conventional method in promoting the adhesion between the rubber and the reinforcement is to incorporate a cobalt compound. Examples of cobalt compounds which are conventionally used include cobalt naphthenate, cobalt linoleate, cobalt stearate, cobalt oleate, cobalt acetate, cobalt neodecanate, cobalt tallate, cobalt resinate, cobalt acetonate, Manoband.TM. C and the like. Conventionally, the anion of these cobalt compounds has not shown to be of a major effect in the rubber stocks to which they are compounded. Whereas there is a continued need for cobalt compounds, there is a remaining desire to find cobalt compounds which are more effective.